Minimally invasive surgery (“MIS”) minimizes the overall trauma of a surgery by performing the procedure through small incisions in the abdominal wall. In comparison to traditional open surgical techniques, MIS offers the patient minimal tissue damage, reduced recovering time and quicker return to normal activities.
One type of MIS is laparoscopy, in which the surgeon performs the operation through small incisions into the abdominal, thoracic or pelvic cavities. Long instruments and a camera are inserted through these incisions and grant the surgeon access to the patient's internal organs with much reduced trauma to the body. An absorbable gas, such as carbon dioxide is used to distend the patient's cavity and provide a larger working space. Many types of surgical procedures can be performed with this method, including nephrectomy, prostatectomy and hysterectomy.
The introduction of robotic laparoscopic techniques has allowed surgeons greater dexterity by increasing the number of degrees of freedom available inside the body. Some robotic systems also include a stereo camera system, meaning the surgeon can see his/her tools and the anatomy in three dimensions, thus regaining depth perception. During robotic surgery, though, the operating surgeon is further separated from the patient and must rely on assistants to interact with the patient. Assistants perform such tasks as passing in suture, controlling suction or controlling an external laparoscopic ultrasound transducer.
Ultrasound is currently used during liver resection to localize and stage the lesions as well as determine the extent of the resection required. Similarly, ultrasound is used during partial nephrectomy to determine the resection margins and identify proper blood flow through the kidney after the tumour is removed. There have also been reports of the use of ultrasound for prostate surgery.
Ultrasound is a user dependent imaging modality, meaning that more experienced ultrasonographers are often able to create better, more informative images than those created by a less experienced user, because the positioning of the transducer imaging region is crucial to the understanding of the underlying anatomy. In addition, hand-eye coordination allows the person holding the ultrasound transducer to better correlate the image shown on the machine with its location in relation to the patient and other anatomy. Unfortunately, during laparoscopic surgical procedures and in particular during robotic laparoscopic procedures, the ultrasound transducer is often controlled by an assistant. This causes additional confusion as the ultrasound operator must position the ultrasound transducer to image tissue that is manipulated (retracted, cauterized, cut, sutured etc.) by the surgeon, and must follow the surgeon's verbal instructions or anticipate the surgeon's needs. This is clearly difficult and limits the use of intra-operative ultrasound.
With more advanced laparoscopic ultrasound techniques, ultrasound could be used more extensively in more procedures, increasing the amount of information available to the surgeon. This additional information could increase the surgeon's efficacy and efficiency as well as the patient's safety.